Regulation of 17α-Hydroxyprogesterone Production during Induced Oocyte Maturation and Ovulation in Amur Sturgeon (Acipenser schrenckii)

In several teleosts, 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) has been identified as a maturation-inducing steroid. DHP is synthesized from 17α-hydroxyprogesterone (17OHP) by 17β-hydroxysteroid dehydrogenase type 12-like (hsd17b12L). Along with 3β-hydroxysteroid dehydrogenase/Δ5-4 isomerase (3β-HSD), 17α-hydroxylase and C17-20 lyase are associated with 17OHP production. This study aimed to determine the roles of Amur sturgeon hsd3b, P450c17-I (cyp17a1), and P450c17-II (cyp17a2) in 17OHP production and to examine their enzyme activity and mRNA expression pattern during oocyte maturation. In the sturgeons used in this study, hsd3b encoded 3β-HSD, cyp17a1 catalyzed 17α-hydroxylase production with C17-20 lyase activity, and cyp17a2 processed 17α-hydroxylase activity alone. In the ovarian follicles of individuals that underwent induced ovulation, hsd3b mRNA levels increased rapidly, cyp17a1 expression was downregulated, and cyp17a2 expression was upregulated during oocyte maturation. Finally, an in vitro study revealed that salmon pituitary extract (SPE) stimulation rapidly induced hsd3b expression, whereas cyp17a1 expression was downregulated. In vitro, cyp17a2 expression did not rapidly increase with SPE stimulation. This rapid upregulation of hsd3b during oocyte maturation was first observed in teleosts. It was suggested that hsd17b12L expression is upregulated after 17OHP production, which is regulated by hsd3b, cyp17a1, and cyp17a2, resulting in DHP production.

Comparative Study on the Natural and Synthetic Hormones ofClarias gariepinus Broodstock

The study was carried out for six (6) weeks at the Department of Fisheries Teaching and Research farm, Modibbo Adama University, Yola, to compare the reproductive performance of Clarias gariepinus using synthetic (ovaprim) and natural (C. gariepinus pituitary extract) hormones . At the end of the feeding trial, the fecundity, percentage fertilization, hatchability, and survival rates of the hatchlings were estimated using standard procedure. The hatchlings were further raised for six weeks and the increase in weight was determined. The results showed that female broodstock injected with C. gariepinus pituitary extract (CgPE) had a higher fecundity (124,000) while the female injected with Ovaprim had 65,000 eggs. The weight of the testes significantly differed (p<0.05) across the treatments, the right lobe weighed 1.63g while the left lobe weighed 1.98g . Subsequently, a higher fertilization rate was recorded in CgPE (91.1%) while Ovaprim had 85.55% . However, Ovaprim had a higher percentage hatchability of 82.93% while CgPE had 82.73% . At the end of the six (6) weeks feeding period, the survival rate was higher in the fish treated with CgPE (82.31%) while the fish injected with Ovaprim had 79.68% . The research exposed the efficacy of using CgPE in the absence of synthetic hormone, CgPE is a preferred substitute that Hatchery managers can utilize for fingerlings production.

Induced reproduction and early development in dourado, Salminus franciscanus Lima & Britski, 2007 (Pisces: Characiformes)

Summary Our study aimed to establish the response of Salminus franciscanus to hypophysation and describe the main morphological events of its embryonic process. Wild fish were captured in São Francisco River and selected broodstock (females: 66.4 ± 11.1 cm and 4.04 ± 2.32 kg; males: 58.3 ± 10.2 cm and 3.62 ± 1.12 kg) were kept at 26.1 ± 0.6°C for induction of final maturation/gamete release via the hypophysation technique. In females, two doses (0.8 and 5.6 mg/kg body weight) of crude pituitary extract of common carp (Cyprinus carpio) were administered with a 14 h interval. For males, a single dose (2.7 mg/kg body weight) of crude pituitary extract was applied at the same time as the females’ second dose. Oocytes and sperm were manually stripped 8 h after a females’ second hormonal dose. Fertilization was carried out using the dry method. Eggs were kept in funnel-type 60 L incubators at 24.3 ± 0.3°C and were analyzed and photographed every 10 min. After hormonal induction, 60% of females and 100% of males reacted positively and no broodstock mortality was recorded. The females released an average of 385.2 ± 78.4 g of oocytes and the fertilization rate observed was 50.4 ± 12.3%. The blastopore closure occurred at 7.5 h, somite formation at 12 h and hatching at 20 h post-fertilization. In general, the results of this study improve the understanding of the reproductive biology of dourado and confirm its potential for fish farming in the neotropical region.

Homoplastic hypophysation of African catfish, Clarias gariepinus

Clarias gariepinus brood stocks (137.0 6.0g) were hypophysised for maturation and ovulation with Clarias crude pituitary extract (CCPE) at 7 mg/kg body weight of female fish. Fertilization was done by mixing egg and mill together in a dry bowl with feather. Physico-chemical parameters of water were maintained at 6.0 +0.2 mg/l (dissolved oxygen), 28.0 +0.5°C (temperature) and 7.2, 0.1 (pH). The latency period recorded for optimal egg was 10-12 hours. While hatching started at 24 hours to 36 hours. The total number of eggs stripped was 618.8 10, the total fertilized was 332.8 x 10', the total fry hatched was 280.6 x 10%. It is concluded that C. gariepinus can be induced with CCPE to reduce the cost of carp pituitary and problem of its procurement due to scarcity.

Equine pituitary extract obtained during summer improves follicular dynamics of mares during autumnal transition period

To compare follicular dynamics after treatment with low doses of equine pituitary extract obtained during winter and summer and to study the relationship between follicular dynamic and environmental parameters, 21 mares were evaluated to follow follicular dynamic and ovulation, from the final of the spring transitional up to the beginning of autumnal transitional period. Mares were randomly designed to one of three treatments: Equine Pituitary Extract from summer (EPE-S), Equine Pituitary Extract from winter (EPE-W) or saline (Control). Treatments were repeated twice: March/2017, after autumnal equinox and April/2017. Temperature, humidity, solar radiation and hours/ light/day were recorded and Temperature Humidity Index (THI) was calculated. Pre-ovulatory follicles reached the greatest diameter (40.7 mm) in December (p<0.05), following the increase in light/hours/day. The smallest pre-ovulatory follicles were verified in February (34.6 mm) and March (35.0 mm) (p>0.05). After EPE, days for ovulation differed, as well as the diameter of pre-ovulatory follicles (p<0.05). EPE-W showed similar follicular dynamics as Control, ovulating smaller follicles (p<0.05) and later (p<0.05) than EPE-S. Temperature and solar radiation did not differ (p>0.05), but humidity and THI differed (p<0.05). THI was not correlated to the diameter of pre-ovulatory follicles (p=0.37), diameter of subordinate follicles (p=0.80), or number/ follicles per ovulatory wave (p=0.98). In conclusion, daylight duration influenced ovarian function; low doses of EPE-S improvede follicular growth and ovulation rate during autumnal transition period of mares; pre-ovulatory follicle diameter increased from the spring to summer, but the time required to reach ovulation decreased.

Monitoring the time-grade required for extrusion of oocytes reproductive from colossoma macropomum

The water temperature of the tanks of the breeding herds exerts a strong influence on the process of artificial reproduction. Its monitoring through the hour-degree, serves to assist in the moment to be made the extrusion of the oocytes. The objective was to monitor the time-degree that Colossoma macropomum females need after the second dose of the hormonal induction protocol, until the time of extrusion of their oocytes. The analysis was carried out at the Fish Fishery in the municipality of Sorriso-MT. Nine breeding women were submitted to the protocol of hormonal induction with pituitary extract of carp being administered in two doses. In the former, the dose of 0.5 mg / kg was used and the second dose was 5 mg / kg body weight, with an interval of 12 hours. From the second dose, the temperature in degrees centigrade of the water from the tanks was monitored hourly until the time of oocyte extrusion. Breeders had muscle tremors, swimming in circles, and were more agitated nine hours after the second dose. The oocytes had a yellowish-brown appearance, and some had individual features. The sum of the temperature of the water in hours-degree obtained was of 243. The temperature of the water did not present variation, maintaining itself at 27 ° C. It is concluded that an hour-degree is necessary for an extrusion of oocytes in some of the things you can find in Colossoma Macropomum of 243, agreeing with the limits proposed in the literature.

Effect of pituitary extract, ovaprim and combination of human chorionic gonadotropin and metoclopramide on reproductive performance of Caspian shemaya, Alburnus chalcoides (Guldenstadt, 1772)

The present study was conducted to examine the effects of three different hormonal treatment types i.e., pituitary extract (Pt), ovaprim (Ov) and human chorionic gonadotropin (HCG) + Metoclopramide (Met) on reproductive performance of Caspian shemaya, Alburnus chalcoides (Guldenstadt, 1772). To this end, three experimental treatments and one control group were considered. The experimental groups were administrated with different doses of Pt, Ov, HCG + Met as follows: Pt [2 mg kg bw (body weight)-1], Pt (3 mg kg bw -1), Pt (4 mg kg bw -1), Ov (10 μg kg bw -1), Ov (20 μg kg bw -1), Ov (30 μg kg bw -1), HCG + Met (1000 IU kg bw -1), HCG + Met (2000 IU kg bw -1), HCG + Met (3000 IU kg bw-1) and also a control group without any hormonal treatment. The highest values of oocyte weight and egg diameter were observed in groups administrated with Ov (10 μg kg bw-1) and HCG + Met (2000 IU kg bw-1) respectively. The highest values of absolute fecundity and relative fecundity were recorded for fish administrated with Ov (20 μg kg bw-1). The latency period and hour-degree for final maturation were lower in fish administrated with Ov (10 μg kg bw-1) compared to other experimental groups (p<0.05). There were no significant differences between experimental groups in terms of other assayed parameters. The results of the present study demonstrated higher efficiency of ovaprim in improving the reproductive performance of Caspian shemaya.